A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 7805200 can be evenly divided by 1 2 4 5 8 10 13 16 19 20 25 26 38 40 50 52 65 76 79 80 95 100 104 130 152 158 190 200 208 247 260 304 316 325 380 395 400 475 494 520 632 650 760 790 950 988 1,027 1,040 1,235 1,264 1,300 1,501 1,520 1,580 1,900 1,975 1,976 2,054 2,470 2,600 3,002 3,160 3,800 3,950 3,952 4,108 4,940 5,135 5,200 6,004 6,175 6,320 7,505 7,600 7,900 8,216 9,880 10,270 12,008 12,350 15,010 15,800 16,432 19,513 19,760 20,540 24,016 24,700 25,675 30,020 31,600 37,525 39,026 41,080 49,400 51,350 60,040 75,050 78,052 82,160 97,565 98,800 102,700 120,080 150,100 156,104 195,130 205,400 300,200 312,208 390,260 410,800 487,825 600,400 780,520 975,650 1,561,040 1,951,300 3,902,600 and 7,805,200, with no remainder.
Since 7,805,200 cannot be divided by just 1 and 7,805,200, it is not a prime number.